Wintering pitcher plants

I have several pitcher plants in containers, sitting on the back deck in direct sun for about 10 hours /day. Some did great, some "survived but didn't thrive" (no explanation on the difference; same soil, same location, same water).

I'm located in western North Carolina, so very close to their native habitat (southern NC). Which is interesting, since no one here has ever heard of them! LOL

The question is, how do I handle them over the winter? Leave them sitting where they are, exposed to frost, snow, and ice?

Do I continue to keep water in the saucer beneath? What about when that water freezes?